1. Field of the Invention
The present invention generally relates to telephonic services and routing technologies and, more specifically, to a system for automatically routing telephone calls.
2. Background of the Invention
In the increasingly competitive business world, there have been various attempts to automatically route telephone calls made to an "1-800" number or equivalent for a local store, franchise, branch, dealer or service company (henceforth, service location) , whose service area encompasses the caller location for the product or service associated with the "1-800" number. For example, a person would dial 1-800-Italian from any Touch Tone.RTM. phone (93 percent of U.S. phones are Touch Tone) in the United States, and the phone would ring at the MyPizza (a fictitious business) service location that delivers pizza to the location of the calling telephone.
There have been several previous simplistic attempts to automatically route calls to a service location that is geographically proximate to the caller. These routing technologies are based on routing the incoming call to a location with the same telephone prefix as the originating call, to the same 5-digit zip code, to all zip codes that have the same city name, or a combination of the above. A telephone prefix or exchange is identified by the middle three digits of a ten digit telephone number. For example, in 619-942-9999, the prefix or exchange is 942. Usually all telephone numbers with the same prefix are serviced by the same wire center. A wire center is the geographical area serviced by a single telephone company office. The wire center is usually one switch, but can be multiple switches, and usually provides service to about ten exchanges. By definition of the telephone companies, wire centers do not overlap.
A. Prior Routing System Structure
The earth is a sphere, and any point on its surface can be defined by a latitude and longitude spherical coordinate system developed several centuries ago. Using this coordinate system, spherical trigonometry, and a computer, it is possible to calculate the distance between any two locations on the earth and determine if one location lies within a specified radius of another or determine if a location is contained within an irregular service area defined as a spherical polygon.
Several years ago, AT&T instituted the technology of passing the calling telephone number along the telephone network, by use of Automatic Number Identification (ANI), to facilitate billing. The "Caller ID" feature, available on some telephone networks, utilizes the ANI technology to identify the telephone number of the calling party. Since a modern telephone switch is just a special purpose computer, it is a simple process for the switch handling the call to look up in a record table (of over one hundred million records) the calling telephone number with an assigned service location telephone number and route the call to the service telephone number.
However, there were some fairly formidable problems that needed to be solved before this routing process could be a commercially viable and practical service. The first problem was initially determining the latitude and longitude of every telephone number in the United States and keeping them updated when twenty percent of the consumer population moves every year and businesses are continually opening and closing locations. The second problem was performing the multitude of spherical trigonometric calculations which is several orders of magnitude beyond today's most powerful computers that are required to create the calling telephone number to the service location telephone number tables and to keep them updated in a constantly changing environment.
Several key databases and technologies are necessary to solve these problems. The United States Census Bureau, as part of the 1990 census, built a national latitude and longitude cartographic map of the United States called TIGER (Topological Integrated Geographical Encoding and Referencing) that contains almost every street link in the United States. A street link is a street segment intersected by other streets at each end. The TIGER record for all street links contains the latitude and longitude coordinates at each end of the street segment accurate to within plus or minus thirty feet and, for most street segments, the starting and ending address ranges for each side of the street. Where the Census Bureau did not complete the address ranges, private companies have filled in the gaps and are updating TIGER as new streets are built.
In the past, the U.S. Postal Service (the "Post Office") divided the U.S. into postal delivery areas called zip (zone improvement plan) codes to help automate the routing of mail. At the nine digit level (called "zip+4"), these zip codes usually correspond to a single side of a street link. In addition to geographically dividing the United States into small postal delivery areas, the Post Office also set standards for the naming of places and streets. For direct mailers to get discounts, they had to standardize their mailing addresses to match the Post Office's naming conventions and provide a zip+4 code. To facilitate the process of postal address standardization and zip+4 coding, the Post Office provides a national Zip+4 Address Coding Guide and has certified several commercially available software packages that correctly address standardize and zip+4 code 99 percent plus of the address records on a Post Office test file. It is well known that file or table records comprise one or more fields.
Recently, the Post Office and some private companies have matched the Post Office's Zip+4 Address Coding Guide with TIGER and have created files containing zip+4 codes with latitude and longitude centroids (a zip+4 centroid is the approximate geographical mid-point of a zip+4 code). This type of file is referred to as a zip+4 latitude and longitude centroid file 100 (FIG. 1a). These centroids are accurate 95 percent of the time to within plus or minus 105 feet in relation to a house or business receiving mail at a street address assigned to a given zip+4 code. Today, it is a very reliable and economical process to address standardize and zip+4 code a list identifying physical locations, such as a master list of phone numbers of the present invention.
Other changes and improvements in telecommunications technology were needed to make the automated telephone call routing process a commercially viable and practical service. Improvements in the telecommunication infrastructure in the U.S. have changed the telecommunication cost structure. Presently the cost of a telephone call from Los Angeles to New York is about the same as for a call from Los Angeles to San Diego. Therefore, the physical location of a central routing switch is no longer critical, or in other words, can be anywhere in the continental U.S.
Another improvement of telecommunications technology is the advent of Geographic Information Systems, commonly called GIS. These systems allow the aggregation and display of almost any data for any area, any size or shape, anywhere in the United States by interactive maps. The popularity of these systems has lead to the development of sophisticated techniques and algorithms to handle geographically based information. Of primary interest is the linking of the geographic information to telephone numbers, especially at the 10-digit level (area code-prefix-suffix).
The complex process of spherical trigonometric distance calculations on billions of possible permutations has been alleviated by making the process less computer intensive. Instead of performing complex trigonometric spherical calculations, a technique that is less than one-thousandth as computer intensive is used. This technique is based on doing a polyconic projection from each service location and performing simple two dimensional distance squared tests. There are approximately 68.9404 miles per degree latitude. However, the miles per degree longitude varies with the latitude. At a given latitude, the miles per degree longitude is equal to the cosine of the latitude multiplied by 68.9404. By using the service location as the latitude point and knowing the latitude and longitude of calling points, it is easy to obtain a delta latitude and longitude, translate them into miles, and perform a simple distance calculation, i.e., "distance=SQRT(X**2+Y**2)". This polyconic projection technique results in a distance calculation error of approximately 12 feet for two locations that are 100 miles apart at 40 degrees latitude. However, additional reduction of the computational effort is necessary to have a practical, efficient, and commercially viable routing process.
B. Prior Routing System Operation
Previous technologies for routing "1-800" telephone number calls to a service location have one or more of the following three problems:
(1) Many such routing systems are very coarse in their level of precision and cannot handle small service areas with legally defined franchise territories like pizza delivery. A much more precise system is desired that is accurate to within 105 feet rather than previous accuracies to within 10 miles. Such a system would utilize very precise distance calculations made possible by knowing the physical location on the earth, most typically expressed as a latitude and longitude, of nearly every non-mobile telephone in the United States. Other coordinate systems could be used in other countries. A business also may like the ability to route a telephone call to a specific franchise territory, which may be an irregularly shaped polygon.
(2) Another problem in routing systems is that they divide the United States into many large arbitrarily defined areas and there is no ability to route a call to the closest service location if the closest location is not located in the same artificially created area as the caller. In many instances, a caller located near the border of an exchange area or 5-digit zip code is much closer to a service location with a different zip code or telephone prefix than the one to which it is routed. A seamless system is desired that does not use artificially created areas such as telephone wire centers, telephone prefixes, or 5-digit zip codes where calls can only be routed within their area. A business may want an option of choosing to route a call to the closest branch or to any branch, for example, in a 5 mile radius of the caller.
(3) Finally, known routing systems often rely on third party telephone directories that are always outdated due to publishing, key entry, and optical character recognition (OCR) scanning time lags and which do not include unlisted numbers. Over 30 percent of the U.S. telephone numbers are unlisted, which includes public pay phones and multiple lines going into businesses and households where only one line is listed. Because consumers and businesses throughout the country change locations on a daily basis, a system is desired that correctly routes a much higher percentage of calls than the previous attempts. In the U.S., such a system would require direct access to the AT&T universe of telephone numbers. Such a system would preferably utilize daily updated and unlisted telephone numbers and involve passing information between regulated telephone databases maintained by the telephone companies and client databases maintained by third parties.
These three deficiencies result in lower customer service and satisfaction, higher costs because of manual exception handling for calls that cannot be routed due to a variety of reasons, costs of misrouting, and high on-going maintenance costs. Manual exception handling generally requires operator intervention in the "1-800" call.
Other previous systems require the consumer to enter their zip code or telephone prefix on the Touch Tone keypad in response to voice prompting from the system. Based on the caller-entered data on the keypad, the telephone call is forwarded to a destination telephone. Other similar systems will simply inform the consumer, by a voice message, of another telephone number for the local dealer, which must be manually dialed rather than forwarding the call automatically. A system is desired that does not require any additional customer interaction or input. Such a system would be totally automatic by utilizing, at a minimum, the 10-digit telephone numbers in the standard telephone packet that can only be accessed and utilized by regulated telephone companies on a national basis. The telephone packet includes the complete origin and destination telephone numbers.
The basis of an automatic telephone routing system must include a means to automatically identify the telephone number of the calling party. Such a system is disclosed by Kaplan, U.S. Pat. No. 5,163,087. This system translates an Automatic Number Identification (ANI) of the calling party into a customer database key previously defined by the called party. The database key, e.g., customer account number, is then provided to the called party instead of the ANI information such that a computer at the called business can process the key to look up and present customer information to an agent of the business. This system assumes that the caller has called this business at a previous time to provide information to the agent of the business to create a customer record or other similar information. The Kaplan system delivers the database key to one business location rather than a plurality of service locations throughout the country. The delivery of the database key to the business requires an Integrated Services Digital Network (ISDN) or similar facility, which is an additional burden for the business.
An automatic routing system should not need to deliver a database key or message to the final destination, but would merely utilize the ANI information as an index to a table containing partitions of a country into small geographic areas, such as postal service zip+4 codes. These partitions would be further utilized to access one of a plurality of service locations that may be anywhere within the country.
A current system for telephone call routing is described in U.S. Pat. No. 4,757,267 to Riskin. Riskin employs automatic number identification (ANI) for routing calls from a caller to a dealer located within the same area code and prefix (first six digits of a 10-digit telephone number, the "6-digit number") as the caller. Because the area identified by the 6-digit number is fairly large and there may be several dealers within the area, the dealer location is usually selected from a list of several locations based on random selection, or weighted percentage assigned to each location. Alternatively, the caller is presented with a list of possible dealer locations for the large geographic area because the system does not know which service locations are closer than the others. Riskin uses the 6-digit number to determine the location of both the caller and the service location. Riskin assumes the location of the caller to be the location of the central office switch that services the caller's 6-digit exchange (which can be 0 to 5 miles from its true location), and assumes the location of the dealer location to be the location of the central office switch that services the dealer location's 6-digit exchange (which can be 0 to 5 miles from its true location) utilizing a coordinate system that is accurate to plus or minus 2300 feet. What is desired is a system that uses all ten digits of the calling and service location telephone numbers and the physical street address of the location of the numbers in connection with a GIS-type database (utilizing a coordinate system that is accurate to within 30 feet) to provide geographic precision to within 105 feet for the location of the calling and destination telephones.
Consequently there is a need for an automated telephone routing system that provides the ability to reduce costs by routing a very high percentage of calls made to a single national telephone number without any human intervention; the marketing advantage for a client of a single, easy to remember, toll free or nominal fee national telephone number; geographically precise results; and the ability of a business to choose among different types of destination service area definitions. Preferably, these service area definitions may include the closest service location to the caller within a predefined distance; all service locations within a specific radius of the caller; and a service location whose service area is defined as an irregular shaped polygon that may or may not overlap with any other polygons.